Loading/unloading device for shelving

ABSTRACT

The invention relates to a rack serving device ( 1 ) with a load-bearing means ( 4 ) displaceable in the height direction of a mast ( 2 ), the mast ( 2 ) being guided by means of bogie assemblies ( 7, 8 ) on bottom and top guide tracks and mounted so as to be displaceable along the guide tracks by means of a bottom and top friction-locking displacement drive ( 13, 14 ). The bottom and the top adjusting mechanisms are guided by means of height and lateral guide elements on the guide track and are designed to be displaceable relative to the guide tracks by means of a drive system ( 33 ). Arranged respectively between the displacement drives ( 13, 14 ) and bogie assemblies ( 7, 8 ) is a coupling mechanism ( 29 ), comprising at least two displaceable coupling parts ( 28 ) and, extending between the articulation axes of the coupling parts ( 28 ), at least one coupling connection ( 27 ) which is pivotable about the articulation axis substantially perpendicular to the longitudinal extension of the guide track relative to a coupling part ( 28 ) and, at an end region remote from this articulation axis, mounted so as to be slideable in a longitudinal guide extending substantially parallel with the longitudinal extension of the mast ( 2 ).

[0001] The invention relates to a lift mechanism of a racking rackserving device, a racking rack serving device for a racking system and arack serving device having the features defined in the generic parts ofclaims 1, 23 and 65.

[0002] A number of different rack serving devices are known, whichessentially differ in terms of the layout of the drives and thestructural design of the mast, namely depending on whether they aresingle-mast or twin-mast systems.

[0003] Patent specification DE 44 05 952 A1 describes a rack servingdevice, which is displaced by means of top and bottom drives, the travelof which is controlled in synchronisation. The rack serving device isguided in an aisle and a lift carriage on its mast carries the loads.The rack serving device transmits its own natural weight and the weightof the loads to be carried via a roller with runs along with it in theaisle. In another embodiment of this invention, the mast is supported atthe top and bottom region in the direction of the aisle by means ofdriven gear wheels in stationary gear racks. The synchronised motion isachieved either by electrical synchronisation or by mechanicallycoupling the two drives. The mast foot and mast head are held verticalone above the other by taking separate measurements of the travel pathsand applying a permanent compensation for any deviations by acceleratingor decelerating at least one displacement drive. The disadvantage ofthis rack serving device is the risk of the rack and pinion drive beingforced due to misalignment of the mast if the electric synchronisationfails. The uneven moment of inertia of the mast foot and mast headdepending on the position of the lift carriage means that greaterdifferences in the braking path between bottom and top traction drivescan be expected, and hence misalignment of the mast. In the case of thisparticular rack serving device, this causes a strong pressure on thesides of the meshing teeth of the rack and pinion drive, which can leadto damage.

[0004] Patent specification EP 0 621 231 A1 discloses a rack servingdevice similar to the one described above, in which the driven gears ofthe synchronously rotated drives are mounted on universal joints inorder to compensate for angular errors and avoid forced pressure.

[0005] The same systems with drives acting in a friction lock are alsoalready known from patent specifications CH 518 862 and CH 518 863. Themast is guided on guide rails by means of guide rollers mountedlaterally at the mast foot and mast head and is supported in a frictionlock in the direction of travel by means of two pinions of a verticalconnecting shaft in a respective top and bottom gear rack. The rackserving device transmits the vertical forces into the bottom rail via aflywheel. Since the mast foot and mast head are forcibly guided, thereis no need to make allowance for a horizontal gear distance. Thedisadvantage of this rack serving device is the highly complexmechanical system needed for the connecting shaft and its mounting onthe mast, as well as the very high costs incurred by the top and bottomgear rack and their accurate laying in the aisle of the racking system.Furthermore, this rack serving device is susceptible to barelycontrollable vibrations under dynamic load because the extremely longconnecting shaft is very easily twisted and acts like a torsion springunder dynamic influences.

[0006] The rack serving devices above known from patent specificationsDE 44 05 052 A1, EP 0 621 231 A1, CH 518 862 and CH 518 863 also haveproblems in terms of noise, lubrication and wear due to the openconstruction of the teeth and the relatively high cost of the materials,assembly and maintenance. The high build-up of noise also means that therack serving devices described above can be used on a limited basisonly. The various disadvantages outlined above are so serious that theserack serving devices have not been able to gain a foothold on the marketto date.

[0007] The above-mentioned disadvantages have been overcome by usingdrives which act on the basis of a friction-locking action. A drive ofthis type for a rack serving device is known from patent specificationDE 44 08 123 A1, which has a drive which can be driven on at least onefloor rail and at least one, but as a rule two, load-bearing wheelssupported on the floor rail. The load-bearing wheels merely take theload of the entire rack serving device and the driving torque istransmitted to the bogie assembly of the rack serving device by at leastone separate friction wheel, which engages on the web of the floor rail.The rails are provided in the form of double-T sections or T-sections,the web of which stands perpendicular to the ground on which the rail islaid and fixed and the load-bearing wheel is supported and rolls on thetop and bottom belt of the rails, whilst the friction wheel engages onthe web. The friction wheels are forced against the web with apre-definable contact force. This contact force can be manually set orautomatically controlled by means of a runner. The disadvantage of thisis that the drive rollers are disposed and roll on oppositely lyingguide rails of the web and also serve as lateral guide members for thebogie assembly frame incorporating the drive. If a mast of a rackserving device of this type is fitted with a bogie assembly driven inthis manner at its mast foot and mast head and the mast moves out ofline from its vertical orientation and/or is subjected to forces actingin the transverse direction to the aisle, the drive rollers will besubjected to increased friction-induced wear, which means that thesebogie assemblies can only be used on rack serving devices of a smallconstruction and operated at low displacement speeds. For this reasonalone, the range of applications for which rack serving devices fittedwith these bogie assemblies can be used is severely limited and theycould not be used, or could be used under limited conditions only, formodern order picking systems where travel speeds of up to 7 m/sec andmast heights of up to 20 m as well as low maintenance are required. Thedeformation occurring caused in the mast during operation alone causesstress on the drive rollers and the increased friction-induced wearmentioned above.

[0008] Patent specifications DE 195 34 291 A1 and DE 196 14 660 A1propose rack serving devices which largely overcome the disadvantagesoutlined above. These rack serving devices have one mast with a liftcarriage which can be displaced on it, which is guided and supported bymeans of a bogie assembly on the bottom and top rail disposed at themast foot and mast head, each of which is fitted with a drive. The mastfoot and mast head are respectively secured to the bottom and top drivenbogie assembly on an articulated bearing, each bogie assembly having twodriveable load-bearing wheels acting by means of a friction lock, whichsit one behind the other on either side of the articulated bearing sothat they can roll on mutually facing top and bottom belts of the bottomand top rails. The load-bearing wheels co-operate with follower rollerswhich can be applied on opposing sides of the top and bottom belt inorder to improve adhesion between the load-bearing wheels and rails. Theload-bearing wheels and follower rollers are made from plastic, inparticular an elastomer. The disadvantage of rack serving devices ofthis type is that the driveable wheels are designed to transmit aforward motion to the bogie assembly in the direction of the aisle onthe one hand and to take the natural weight of the mast and the load tobe carried on the other, which means that high friction forces occurbetween the load-bearing wheels and the bottom rail, especially whensubjected to high loads, and the requisite driving torque of the drivemotor has to be significantly increased in equal measure, adding extracosts to the production of the rack serving device and requiring morespace in view of the more robust motors needed for the bogie assembly.

[0009] The objective of the invention is to propose a highly dynamicrack serving device that is simple in construction, low in maintenanceand not susceptible to much wear, and which reduces mechanical stress onthe guide rails and guide elements, whilst increasing the availabilityof the rack serving device.

[0010] This objective is achieved by the invention on the basis of thefeatures defined in the characterising part of claim 1. The surprisingadvantage of this approach is that because the linkage point of thedrive mechanism is offset, the height and/or lateral guide elements andguide rail are relieved of load, at least whilst the load-bearing meansis being displaced, and the lifting mechanism is operated in amechanically more gentle way. Offsetting the linkage point of the drivemechanism and relieving the rail of load enables the mast to be made ina thin-walled construction and permits an increase in the displacementspeed of the lift carriage and rack serving device along the rails,whilst also permitting bigger mast heights.

[0011] The embodiment defined in claim 2 provides a simple means ofadditionally reducing the mechanical strain on the height and/or lateralguide elements and guide rail because they are relieved of load duringboth the upward and the downward displacement. As a result of anopposing force acting at the linkage points of the lift carriage,extremely high loads can now also be handled by the load-bearing meanswith relatively little stress on the guide rail and the height and/orlateral guide elements.

[0012] The embodiments defined in claims 3 to 7 have been found to offeradvantages because tried and tested system of drive mechanisms of simpleconstruction can be used and the fact of providing anchoring legs at thefirst and second linkage point makes it possible to transmit a forwardmotion and supporting force via several drive elements, therebyproviding a simple option of adapting to different load capacities ofrack serving devices, and any difference in length caused by wear due toage can be compensated by using several drive elements.

[0013] Also of advantage is the embodiment defined in claim 8, which nowenables lift mechanisms of this type to be used on rack serving devices,even at high temperatures of between 0° C. and −40° C., for example,whilst preserving the properties demanded of the lift mechanism duringdynamic operation in terms of acceleration, travel speed, etc. of theload-bearing means and the properties of the belt-type drive element,such as robustness, dynamic properties, etc. Even temperaturefluctuations of between +15° C. and −40° C., for example, will have noeffect on the elasticity and toughness of the drive element and hencethe dynamic operation of the load-bearing means, such as accelerationand travel speed. Regulating the temperature in or on the drive elementprimarily permits a slip-free dynamic displacement of the load-bearingmeans and in a broader sense is gentler on the height and/or lateralguide elements.

[0014] The embodiments defined in claims 9 and 10 provide a simple meansof adapting to different operating conditions or structuralspecifications such as the length and width of the drive element ormounting space, etc., of the rack serving devices.

[0015] The embodiments defined in claims 11 and 12 are of advantage inthis respect, since they enable the stationary device supplying power tobe mounted and/or retrofitted without much in the way of structuralcomplexity and the material of the drive element as well as the point atwhich it will be mounted can be adapted to different requirements suchas temperature range, for example. Because the device is operated byalternating current, changes in magnetic flow can be used to produce therequisite induction of voltage or current and the effect of convertingthe electrical power into the heat which occurs as the current passesthrough an ohmic resistor can be used to heat the drive element, inparticular a cogged belt, throughout its cross section and entire lengthto an essentially uniform, pre-definable minimum temperature ofapproximately +5° C. to +25° C., in particular +10° C. to +22° C., forexample +20° C., if operating at ambient temperatures of −10° C.

[0016] The embodiments defined in claims 13 to 15 enable the use ofstandardised, inexpensive and extensively proven devices such asinduction coils, microwave generators, heating devices or such like,thereby making the system reliable. Another advantage primarily residesin the fact that the device as such is already optimised and is alsorelatively small in terms of its dimensions, so that the space needed toaccommodate the device can also be kept to a minimum.

[0017] Also of advantage is the embodiment defined in claim 16, whichdispenses with the need for any additional fixtures on the rack servingdevice.

[0018] The advantage of the embodiments defined in claims 17 to 20 isthat the reinforcing support, which is usually provided in the driveelement as a matter of course anyway, can serve as the ohmic resistordetermining the energy loss, which means that all drive elements knownfrom the prior art that are also suitable for transmitting high forcescan be used.

[0019] The embodiment defined in claim 21 enables the temperature set inor on the drive element to be directly detected using inexpensive, triedand tested systems known from the prior art, thereby enabling the statusof the drive element to be permanently monitored if necessary.

[0020] The embodiment defined in claim 22 is also of advantage becausethe fact of pre-defining a control algorithm and the incoming actualvalue of the temperature via the measuring means and optionally ofpre-defining the ambient temperature, means that a pre-definedtemperature can be set which is optimised for these conditions, afterwhich the actual value can be permanently controlled and adapted to aselected temperature desired value by the closed automatic controlcircuit on the basis of the control algorithm and detected parameters.

[0021] The objective of the invention is also achieved as a result ofthe features defined in the characterising part of claim 23. Theadvantage resides in the fact that, because the bogie assemblies anddisplacement drives are of a separate construction and because they aredrivingly linked by means of the coupling mechanisms, the bogieassemblies are able to withstand static and dynamic inertial forces,whereas the displacement drives, which are small in terms of theirdimensions and separately driven, are required exclusively to generatethe forward motion for the rack serving device and do not have tosupport any loads of the rack serving devices or the loads to betransported, which enables the rack serving device to be operated forlong periods without any maintenance and also significantly improves thedriving dynamics.

[0022] Also of advantage are the embodiments defined in claims 24 and25, whereby the forces of forward motion of the bottom and topdisplacement drive acting on the coupling parts and linkage points,which are arranged offset transversely to the longitudinal extension ofthe guide rails of the guide rails on the bottom and top bogie assemblyor mast foot and mast head, reduce mechanical stress on the height guideelement and the guide rail part of the bottom drive rail supporting theheight guide element as the mast is moved along the guide rails.

[0023] As defined in claim 26, the mast is guided separately by thebogie assemblies in the height direction and at the side.

[0024] Also of advantage are the embodiments defined in claims 27 to 29,providing a displacement drive that is prevented from turning, which isguided in the height direction and at the side and forms a separate unitfrom the running rail, as well as being small in dimension andinexpensive.

[0025] Various embodiments of the displacement drives with advantageousconstructions are defined in claims 30 and 31.

[0026] As defined in claim 32, the use of elastomers or steel encased inplastic for the height guide, lateral guide, drive and contact elementsof the bogie assemblies and displacement drives keeps noise to a minimumduring operation of the rack serving devices. Another advantage is thefact that these materials have a high force-slip coefficient, whichenables the requisite driving forces to be transmitted, even insituations of high acceleration and deceleration. As a result of thenoise-reducing features, the rack serving device generates a low soundpressure level, even at very high speeds, and can therefore also be usedwhere people are around.

[0027] Also of advantage is the embodiment defined in claim 33, wherebythe vertical displacement path or height displacement of theload-bearing means is such that the load-bearing means can be movedessentially along and over the entire height of the mast.

[0028] In the case of the embodiments defined in claims 34 and 35, thedisplacement drive and the bogie assembly each constitutes a separateunit and they can be coupled or connected to one another, preferablyreleasably, by means of at least one coupling mechanism. The bottom andtop bogie assembly guide the mast in the direction of its height and atthe side and form a self-supporting system, the advantage of which isthat if a displacement drive is defective, once the connection betweenthe bogie assembly and the displacement drive has been uncoupled orreleased, it can be taken off the rail and an operation-readydisplacement drive immediately fitted on the rail again. This reducescost-intensive down times and any repair and/or maintenance work whichis needed can be easily carried out away from the working area of therack serving device.

[0029] Also of advantage are the embodiments defined in claims 36 to 39,because if the mast shifts from its vertical position, the runner, whichis pivotably mounted in the bogie assembly, is automatically moved intoa pre-definable horizontal position and the lateral guide elements runparallel with the aisle direction, thereby avoiding any wear which mightotherwise occur if the lateral guide members were to assume inclinedpositions. The wiper bar, which fulfils various functions, serves on theone hand as a cleaning mechanism for the guide tracks, in particular therails, and on the other hand as a support element for the returnelements disposed between the base and it, thereby ensuring that if themast assumes a crooked position, the runner or the lateral guideelements is or are automatically moved into a horizontal position,thereby providing an optimal lateral guiding action irrespective of theoperating position of the mast.

[0030] As a result of an embodiment defined in claim 40, the forwarddisplacement forces can be transmitted by the displacement drives to thebogie assemblies without any backlash.

[0031] Also of advantage are the embodiments defined in claims 41 and42, because any deviations in the linearity of the rails can becompensated between bogie assemblies and displacement drives, whichprevents the latter from being forced.

[0032] As defined in claim 43, the coupling connections disposed betweenthe bogie assemblies and displacement drives ensure that if the mastdeviates from its vertical position, it can be positioned in two spatialdirections without any clearance relative to the displacement drives.Any changes in length or deformations in the mast caused by repairs orstress and any inaccuracies in the way the guide tracks are laid can becompensated by the coupling mechanisms.

[0033] The embodiments defined in claims 44 to 49 are also of advantagebecause they offer a coupling mechanism capable of transmitting highforward forces, enabling the forward force of the displacement drive tobe transmitted to the mast, in particular the bogie assembly, withoutany clearance.

[0034] Claims 50 and 51 define advantageous layouts and structuraldesigns of the coupling mechanisms.

[0035] The embodiments defined in claims 52 and 53 eliminate the risk ofthe mast tipping over or lurching, even if it assumes an inadmissiblycrooked position. This mechanical safety feature is easy to produce andinexpensive to make and the anti-lift system can be easily fitted on themast foot and mast head.

[0036] Also of advantage are the embodiments defined in claims 54 to 56,whereby the location of the rack serving device and/or the position ofthe load-bearing means on the rack serving device can be exactlydetected within a pre-definable operating range and the data and signalsacquired as a result can be used for further processing, for example fora control system, thereby permitting fully automated operation in anorder picking system.

[0037] Also of advantage is the embodiment defined in claim 57, wherebyimage-processing elements can be provided in regions that are difficultto access, such as on the bogie assembly and/or displacement drive inthe mast head region in order to detect data as a means of monitoringstatus and/or generating maintenance prognoses, and the data is thenforwarded to a control system, where it can be simply evaluated andfurther processed. Shelves can be monitored by providingimage-processing elements on the load-bearing means, for example, whichmeans that as they are approached, it will be possible to ascertainwhether the shelves of a racking system are occupied. The data detectedby the image-processing elements and forwarded to the control system canthen naturally also be transmitted via local-area and/or worldwidenetworks, such as an intranet, the Internet, for example, for remotemaintenance purposes.

[0038] Also of advantage is the embodiment defined in claim 58, wherebyeven slight deviations of the load-bearing means from its preferablyhorizontal orientation can be detected by means of a sensor systemdisposed on the load-bearing means, in which case an adjustment can bemade to the driving torque of the drive roller and the forward speed ofat least one displacement drive so that the load-bearing means ishorizontally aligned, as a result of which the load-bearing means can beused as a reference level on the basis of which the lift carriage can beexactly positioned during the process of storage in or retrieval from ashelf. Detecting the exact position of the load-bearing means enablescollisions to be avoided when storing and/or retrieving a pallet in theshelf, for example.

[0039] An embodiment defined in claim 59 enables at least one tractiondrive to be controlled depending on a load to be placed on theload-bearing means, depending on which the contact force of the driveelements on the rails can be adjusted, thereby essentially preventingany slip between the drive elements and the rails during the drivingprocess.

[0040] The embodiments defined in claims 60 to 64 enable at least oneladder displaceable along a rail to be moved into position to permitmaintenance work to be carried out rapidly on the rack serving device.

[0041] Finally, the objective is achieved by the invention as a resultof the features defined in claim 65. The surprising advantage of thisapproach is that a plurality of rack serving devices of the same typecan be used in any combination with one another and can be assembledwith one another to produce one rack serving unit, offering an easy mixand match system to meet different requirements, for example thegeometry of the goods being conveyed, the load-bearing capacity of therack serving device, keeping count of warehouse turnover, etc. Thisability to use the rack serving devices in any combination offers a highdegree of flexibility, in keeping with modern automation systems,without involving much in the way of extra work in terms of assembly.

[0042] In one advantageous embodiment defined in claim 66, a supportframe attached to the mast foot and mast head enables a frame-type rackserving device with two masts to be created, thereby enabling it to bemodified to cater for different applications. Since the rack servingdevices are built in a modular structure, the refitting work needed forthis purpose can be carried out very rapidly and easily.

[0043] The embodiment defined in claim 67 enables warehouse turnover tobe increased because goods can be handled by several rack servingdevices simultaneously.

[0044] An embodiment defined in claim 68 is also of advantage because ofthe pitch of the mast in a plane parallel with the aisle direction,which means that the forces transmitted to the mast by the guideelements or load-bearing wheels supported on the lift mechanism areuniformly distributed throughout the profile cross section, becausethere are no points at which the material comes into contact in theimmediate vicinity of the guide tracks and running surfaces. This meansthat a mast can be made with less thick materials but will still becapable of withstanding the same or higher loads, both in static anddynamic terms.

[0045] The advantage of this is that, in addition or merely by dint ofthe joining technology and manufacturing method used, namely a weldingprocess, in particular MIG welding, dynamic stress, in particularvibrations of the mast, caused by acceleration and deceleration can beuniformly distributed in the longitudinal direction, avoiding peakstresses. As a result of the higher elasticity and the lower brittlenessobtained by the fact that less heat is introduced into the mast duringthe welding process, particularly in the area of the weld joints,strength and durability are significantly increased, even when subjectedto vibration-induced stress. The half-shell design in which joiningregions with a large surface area mutually overlap or sit one on top ofthe other enables forces to be spread over a significantly largersurface area in the joint regions, which reduces peak stress, and theabutting longitudinal sections promote a capillary effect during thewelding process so that the solder migrates or penetrates the jointregions effectively, compensating for any unevenness between abuttingregions of the elongate sections.

[0046] The embodiments defined in claims 69 to 72 are of advantagebecause the protuberances constituting the guide tracks and theprojections disposed at a right angle to the protuberances and formingthe guide tracks on the one hand guide the load-bearing wheels and onthe other hand impart a high degree of rigidity to the mast, even if ithas a small cross section, enabling it to be subjected to high staticand dynamic loads without being inadmissibly deformed. Another advantageis the fact that because the heat transmitted during the solderingprocess is low, the longitudinal sections, which have alreadyessentially assumed their ultimate dimensions, do not becomeinadmissibly warped, thereby enabling the soldering process to be easilycontrolled.

[0047] Also of advantage are the embodiments defined in claims 73 and74, because the welded joint can be individually adapted to suitpre-defined maximum static and dynamic loads.

[0048] As a result of claim 75, the cutouts provided in the mastfacilitate the assembly and/or laying of power-transmitting cables, forexample.

[0049] The U-shaped protuberances provided in the stiffening elements asdescribed in claims 76 to 84 further increase the rigidity andload-bearing capacity of the mast because the forces transmitted by theload-bearing wheels onto the running surfaces of the protuberances arenot only absorbed by the section strips but also by the stiffeningelements in the regions adjoining the protuberances, so that the guidetracks standing proud of the side of the mast enable a high runningaccuracy for the lifting mechanism and the load-bearing means throughoutthe entire operating time.

[0050] Finally, however, the embodiment defined in claim 85 is also ofadvantage because the mast is able to absorb forces throughout itsentire cross section and is a lightweight construction.

[0051] The invention will be described in more detail below withreference to examples of embodiments illustrated in the appendeddrawings.

[0052] Of these:

[0053]FIG. 1 is a highly simplified, schematic diagram giving a sideview of a bottom and top guide track, in particular a bottom and toprail, and the rack serving device proposed by the invention;

[0054]FIG. 2 is a highly simplified, schematic diagram showing a partregion of the top rail and the mast head;

[0055]FIG. 3 is a highly simplified, schematic diagram showing a planview of a bogie assembly and a traction drive drivingly linked to it,the top rail being indicated by broken lines;

[0056]FIG. 4 is a highly simplified, schematic diagram illustratinganother embodiment of the bottom bogie assembly with a runner supportingthe lateral guide elements, seen in section transversely to the aisledirection;

[0057]FIG. 5 is a highly simplified, schematic diagram showing a sideview of a part region of the rack serving device with a lift mechanismproposed by the invention;

[0058]FIG. 6 is a highly simplified schematic diagram showing a sideview of a part region from FIG. 1 with the bottom rail, the mast footand bottom bogie assembly, and an anti-lift mechanism disposed betweenthe rail and the bogie assembly;

[0059]FIG. 7 is a highly simplified, schematic diagram showing a sideview of the rack serving device and a ladder which can be displacedtowards the rack serving device on at least one runner track for thepurpose of carrying out maintenance work;

[0060]FIG. 8 is a highly simplified, schematic diagram showing a sideview of one possible way of integrating several rack serving devices toform one racking rack serving unit;

[0061]FIG. 9 shows a cross section through a mast with the lateral guideelements of the lift carriage lying against the guide tracks;

[0062]FIG. 10 is a highly simplified, schematic diagram showing a frontview of the mast;

[0063]FIG. 11 is a highly simplified, schematic diagram illustrating afront view of the stiffening element;

[0064]FIG. 12 is a highly simplified schematic diagram illustrating anend-on view of the stiffening element illustrated in FIG. 11.

[0065] Firstly, it should be pointed out that the same parts describedin the different embodiments are denoted by the same reference numbersand the same component names and the disclosures made throughout thedescription can be transposed in terms of meaning to same parts bearingthe same reference numbers or same component names. Furthermore, thepositions chosen for the purposes of the description, such as top,bottom, side, etc, relate to the drawing specifically being describedand can be transposed in terms of meaning to a new position when anotherposition is being described. Individual features or combinations offeatures from the different embodiments illustrated and described may beconstrued as independent inventive solutions or solutions proposed bythe invention in their own right. It should be pointed out from theoutset that the rack serving device 1 proposed by the invention issuitable for travelling in straight lines only.

[0066] FIGS. 1 to 3, which will be described together, illustrate a rackserving device 1 with part regions of it illustrated from differentperspectives. The rack serving device 1 has a mast 2, which ispreferably disposed in a substantially vertical arrangement, with a liftcarriage 3 incorporating a load-bearing means 4 which can be displacedin the direction of its height and bogie assemblies 7, 8 at its mastfoot 5 and mast head 6. A load 9 supported on the load-bearing means 4can be stored in and retrieved from a racking system, not illustrated indetail, by appropriate means, which are also not illustrated. The bottombogie assembly 7 is disposed on the mast foot 5 and the top bogieassembly 8 is disposed at the mast head 6. The bottom and top bogieassemblies 7, 8 are respectively guided at the side on at least oneessentially vertical guide track part 10 of a bottom and top guide rail11, 12 and by means of at least one other, substantially horizontalguide rail part in the height direction, which will be described in moredetail below. The bogie assemblies 7, 8 differ from one another in termsof their structural design. The guide rails 11, 12 forming the guidetracks are secured to the building or racking so as to be stationary andare rectilinear in design. A displacement drive 13, 14 co-operatesrespectively with the mast foot 5 and mast head 6 in order to transmit aforward motion to the mast 2 in the aisle direction—indicated by doublearrow 15. The bogie assemblies 7, 8 and displacement drives 13, 14disposed one after the other in the aisle direction—indicated by doublearrow 15—which can be displaced on the bottom and top guide track, inparticular the bottom and top runner rails 11, 12, separately guided inthe height direction and at the side, are drivingly linked to oneanother. The bottom and top displacement drives 13, 14 are preferablydisposed one above the other on the rear face of the mast 2, on thebottom and top runner rails 11, 12. Naturally, it would also be possiblefor a respective displacement drives 13, 14 to be disposed one on eitherside of the mast 2. The displacement drives 13, 14 constitute a top andbottom adjusting mechanism. Also on the rear face of the mast 2 is acontrol cabinet 16, which contains, amongst other things, the controlsystem, the automatic control system and operating electronics for alift motor of the lift carriage 3, the displacement drives 13, 14 andsuch like. The guide tracks and the runner rails 11, 12 constitutingthem are preferably of a flange shaped design in the shape of an I-rail.Contact wires, not illustrated, are disposed on the bottom runner rail11 on a vertical web 17, which supply the rack serving device 1 withpower and by means of which a data exchange can be run from thestationary warehouse management computer to the rack serving device 1and back. Naturally, the contact wire may also run parallel with and ata distance from the runner rail 11.

[0067] The bottom bogie assembly 7 has at least one height guide element20 which rolls on the horizontal guide track part 19 formed by a topbelt 18 of the runner rail 11. The bottom bogie assembly 7 may naturallyalso have a series of load-bearing height elements 20 disposed one afterthe other in the aisle direction—indicated by double arrow 15—, inparticular height guide rollers. In the embodiment illustrated as anexample here, the height guide element 20 is provided in the form of aguide roller made from steel, which may or may not have a plastic sheathsurrounding the running surface. A rotation axis 21 of the height guideroller extends transversely to the aisle direction—indicated by doublearrow 15—or longitudinal extension of the runner rail 11. A housing-typesurrounding frame 22 forming the bogie assembly 7 houses the rotationaxis 21 and supports the height guide roller by means of a bolt disposedin the surrounding frame 22. The surrounding frame 22 has a U-shapedcross section and bears at least one lateral guide element 24 on each ofits side walls 23, spaced apart from one another by a distancecorresponding at least to the width of the top belt 18, disposedadjacent to the vertical guide track parts 10 of the web 17 of thebottom runner rail 11. The lateral guide elements 24 are expedientlyjoined to the bogie assembly 7 in an articulating arrangement so thatthe rotation axes 25 of the lateral guide elements 24 are alwaysoriented perpendicular to the aisle direction—indicated by double arrow15- and parallel with the guide track parts 10, even if the mast 2assumes a crooked position. A guide mechanism incorporating the bottombogie assembly 7 also incorporates the height guide element 20 and thelateral guide elements 24.

[0068]FIG. 1 illustrates the bottom bogie assembly 7 with four lateralguide elements 24, the lateral guide elements 24 being arranged in pairsadjacent to one another on the side walls 23 and one after the other inthe aisle direction—indicated by double arrow 15. Naturally, it wouldalso be possible for the bogie assembly 7 to have only two lateral guideelements 24 arranged one after the other in the aisledirection—indicated by double arrow 15- and diagonally offset from oneanother. In the most basic situation, the lateral guide elements 24 mayalso be provided in the form of lateral guide rollers with rotation axes25 disposed perpendicular to the runner rail 11 and substantiallyparallel with the guide track parts 10. Provided respectively on a rearwall 26 of the bogie assembly 7 or on the rear wall of the mast foot 5and on the displacement drive 13 is at least a first linkage point fortransmitting or applying a forward force or forward motion from thedisplacement drive 13 to the bogie assembly 7. A coupling connection 27,which will be described in more detail below, extends between theselinkage points.

[0069] In this embodiment, the first linkage point of the displacementdrive 13 is disposed on the bogie assembly 7 transversely to thehorizontal guide track part 19, offset in the direction of the mast foot5. The mechanical load to which the guide track parts 19 is subjectedcan be further reduced by arranging the linkage point of thedisplacement drive 14 on the bogie assembly 7 transversely to thehorizontal guide track part 19, offset in the direction opposite themast foot 5. The at least one first linkage point consists of a couplingpart 28 rigidly mounted on the mast 2 or bogie assembly 7. The driveconnection consists of at least one coupling mechanism 29 between thebogie assembly 7 and the displacement drive 13 and the other linkagepoint between the mast-side linkage point and the other linkage pointspaced apart from it on the side of the displacement drive, so that thecoupling mechanism 29 can effect a pivoting motion in at least one ofthe linkage points of the bogie assembly 7 and/or displacement drive 13.The mast-side linkage point and the drive-side linkage point arepreferably disposed on the same side as that at which the mast-sidelinkage point is displaced, above and below the guide track parts 19.Naturally, it would also be possible for the mast-side linkage point tobe disposed above the guide track parts 19 and the drive-side linkagepoint to be disposed underneath, or the mast-side linkage point could bedisposed underneath and the drive-side linkage point on top. A moredetailed description of the structural design of the linkage points andthe coupling mechanism 29 will be given with reference to FIGS. 2 and 3.

[0070] As may be seen by looking at FIG. 1 in conjunction with FIG. 3,the displacement drives 13, 14 each constitute a separate unit drivinglylinked to the bogie assemblies 7, 8, whereby the displacement drives 13,14 are guide by their at least one height guide element 30 and at leastone lateral guide element 31 on guide track parts 19, 32 in the heightdirection and at the side, and can be displaced in a straight line bymeans of at least one drive mechanism 33 along the bottom and top runnerrails 11, 12.

[0071] The height guide elements 30 are provided in the form of heightguide rollers with rotation axes 34 extending transversely to the aisledirection—indicated by double arrow 15—and longitudinal extension of therunner rails 11, 12 and parallel with the guide tracks 19; 32 and thelateral guide elements 31 are provided in the form of lateral guiderollers with rotating rotation axes 35 extending perpendicular to theaisle direction—indicated by double arrow 15—and longitudinal extensionof the runner rails 11, 12 and parallel with the guide track part 10.

[0072] Each of the displacement drives 13, 14 has at least two pairs ofheight guide elements 30 spaced apart from one another in the aisledirection—indicated by double arrow 15—on either side of the web 17 ofthe preferably I-shaped runner rails 11, 12, which sit against guidetrack parts 19, 32 of the bottom and top runner rails 11, 12 facing awayfrom one another and at least one contact element 36 abutting with guidetracks 32, 19 of the mutually spaced top and bottom runner rails 11, 12and preferably at least two pairs of lateral guide elements 31 spacedapart from one another in the aisle direction on oppositely lying guidetracks 10. The height guide elements 30 and contact elements 36 mayoptionally be linked to one another by means of an endlessly circulatingtraction means.

[0073] Naturally, another option would be to provide two height guideelements 30 one after the other in the aisle direction—indicated bydouble arrow 15—diagonally offset from one another to provide a heightguide for the displacement drives 13, 14 and two lateral guide elements31 one after the other in the aisle direction—indicated by double arrow15- and diagonally offset from one another providing a lateral guide.

[0074] The contact elements 36 are provided in the form of pressurerollers which are elastically deformable in the radial direction andhave rotation axes disposed transversely to the aisledirection—indicated by double arrow 15- and longitudinal extension ofthe runner rails 11, 12, applying a contact force in the direction ofthe guide track part 19; 32.

[0075] The drive mechanism 33 of the adjusting mechanisms and thedisplacement drives 13, 14 forming it each have at least one driveroller 37, which can be driven by a drive motor, which engages on theguide track part 10 of the web 17. Naturally, it would also be possibleto provide several driven drive rollers 37 engaging on the oppositelylying guide track parts 10 of the web 17, as illustrated in FIG. 3, orat least one non-driven follower wheel could be provided, which ispressed against the guide track parts 10 with a pre-definable contactforce. The rotation axis of the drive roller 37 extends parallel withthe rotation axes 35 of the lateral guide rollers and perpendicular tothe longitudinal extension of the runner rails 11, 12. The drive torqueof the drive roller 37 is therefore transmitted by a friction lock,thereby applying a forward motion to the displacement drives 13, 14 andbogie assemblies 7, 8. The drive motor of the displacement drives 13, 14may be a servo motor or stepper motor, which is preferably linkeddirectly to the drive roller 37, or an asynchronous motor or synchronousmotor with a gear mechanism between it and the drive roller 37.

[0076] The height and/or lateral guide rollers of the displacementdrives 13, 14 may be manually or automatically adjusted in order toobtain a secure contact or rolling action and a reliable transmission ofthe driving torque on and to the guide tracks 10, 19, 32. A housing 38which essentially surrounds the runner rails 11, 12 supports the drivemotor and has appropriate means for mounting the height and lateralguide elements 30, 31, 36 so that they can be displaced in rotation.

[0077] Although not illustrated, the height and/or lateral guideelements 30, 31 of the displacement drives 13, 14 are respectivelydisposed on a common support frame and the height and/or lateral guideelements 30, 31 are pushed against the guide track parts 10, 19, 32under the action of at least a contact force acting on the supportframe.

[0078] The top bogie assembly 8 drivingly linked to the top displacementdrive 14 via the coupling mechanism 29 has two pairs of lateral guideelements 24 spaced apart from one another in the aisledirection—indicated by double arrow 15—on oppositely lying guide trackparts 10 of the top guide track or runner rail 12, which are preferablyprovided in the form of lateral guide rollers rolling along the guidetrack parts 10 and which rotate about the rotation axis 25 extendingperpendicular to the longitudinal extension of the runner rail 12. Thetop bogie assembly 8 attached to the mast head 6 is essentially providedin the form of a support frame 39 supporting pairs of lateral guideelements 31 disposed one after the other in the aisledirection—indicated by double arrow 15. The support frame 39 is designedwith structural means for mounting the lateral guide rollers. As may beseen from FIG. 3, there are also 2 pairs of output elements for a liftmechanism, which will be described in more detail below. In respect ofthe top bogie assembly 8, it would naturally also be possible for it tohave only two lateral guide elements 24 disposed one after the other inthe aisle direction—indicated by double arrow 15- and arranged offsetfrom one another, in particular lateral guide rollers. A guide mechanismincorporating the top bogie assembly 8 also incorporates the lateralguide elements 24.

[0079] It should be pointed out at this stage that it would also bepossible for the height and lateral guide elements 20, 24; 30, 31 of thebogie assemblies 7, 8 and/or displacement drives 13, 14 to be providedin the form of guide bars which can be applied to the guide track parts19, 32, 10 with a pre-definable contact force, although this option isnot illustrated.

[0080] As a result of the bottom bogie assembly 7 at the mast foot 5co-operating with the top bogie assembly 8 at the mast head 6, the mast2 constitutes a system whereby a forward motion can be transmitted viathe linkage points in the region of the mast foot 5 and mast head 6 bythe displacement drives 13, 14 to enable it to be displaced along thebottom and top runner rail 11, 12, guided in the height direction and atthe side.

[0081] The at least one other linkage point on the top bogie assembly 8is disposed transversely to the horizontal guide track part 19,expediently offset in the direction towards the mast 2, or optionally inthe other direction. The mast-side linkage point and the drive-sidelinkage point are preferably disposed on the same side as that to whichthe mast-side linkage point is offset, optionally above or expedientlyunderneath the guide track part 19. Consequently, at least when the mast2 is being moved along the guide tracks or guide rails 11, 12, thebottom height guide element 20 and the bottom guide track or bottomrunner rail 11 is relieved of pressure.

[0082] As briefly described above and illustrated more clearly in FIG.2, the coupling mechanism 29 is actively connected to at least one otherlinkage point disposed on the mast head 6. In addition to the couplingpart 28 arranged on the mast 2, the coupling mechanism 29 also has atleast one other coupling part 40 disposed on the displacement drive 13,14, between which the coupling connection 27 linking the two extends.

[0083] The coupling mechanism 29, which is essentially of a fork-shapeddesign, has two jaw parts 41 spaced apart from one another transverselyto the longitudinal extension or aisle direction—indicated by doublearrow 15—mounted so as to be pivotable about drive-side coupling parts40, which are preferably disposed in a triangular-shaped arrangement.The jaw parts 41 have at least two guide elements 43 in their cornerregions directed towards the mast 2 and another guide element 43substantially in the region of a centre of gravity of the jaw parts 41.

[0084] The coupling mechanism 29 has at least two articulation axes 42a, 42 b, one of which articulation axes 42 a directed towards the bogieassembly 7, 8 coincides with the mast-side coupling part 28, whilst theother articulation axis 42 b spaced apart from it and directed towardsthe displacement drive 13, 14 coincides with the drive-side couplingpart 40. The coupling part 40 and an and of the coupling connection 27directed towards it each have a bore with a coupling pin extendingthrough it, the longitudinal mid axis of the coupling pin and thearticulation axis 42 b of the coupling part 40 extending congruentlywith one another. In order to accommodate the displacement drive 13, 14so that it can rotate relative to the bogie assembly 7, 8, the couplingconnection 27 is mounted so as to be elastic in the longitudinaldirection of the coupling pin by means of a rubber compensating elementdisposed in the region of the articulation axes 42 a; 42 b.

[0085] The coupling part 28 incorporating the first mast-side linkagepoint has at least one, preferably two mutually spaced, section-typelongitudinal guides 44 corresponding to the guide elements 43 andextending substantially parallel with the longitudinal extension of themast 2, the resultant vertical guide tracks 45 of which serve as asupport for the guide elements 43. Mechanical means, for exampledisplaceable eccentrics, enable a clearance-free adjustment of the guideelements 43 relative to the guide tracks 45 and the mast 2 is connectedto the bottom and top displacement drive 13, 14 without any clearance sothat the forward motion can be transmitted at least in the aisledirection—indicated by double arrow 15. If the mast 2 happens to deviatefrom the vertical position, the coupling mechanism 29 permits a pivotingmotion about the articulation axis 42 b and a vertically guided changein the position of the mast 2, as the rolling guide elements 43 arevertically displaced along the guide tracks 45. The mast 2 therefore hastwo degrees of freedom in the direction of its longitudinal extensionand in the aisle direction—indicated by double arrow 15. As a result,even if the mast 2 assumes a crooked position, it can be maintained inposition without being forced at the mast foot 5 and mast head 6relative to the displacement drives 13, 14. The fact that a clearance isleft free between the guide elements 43 and the longitudinal guides 44transversely to the longitudinal extension of the runner rails 11, 12enables any deviations in the linearity of the runner rails 11, 12 to becompensated, which prevents the bogie assemblies 7, 8, which are guidedin the height direction and to the side, and displacement drives 13, 14from being clamped against one another.

[0086] Although not illustrated, another embodiment designed tocompensate for deviations in the linearity of the runner rails 11, 12 isone in which the bogie assemblies 7, 8 and displacement drives 13, 14are guided relative to one another without any clearance by means of thecoupling mechanism 29 transversely to the longitudinal extension of therunner rails 11, 12 and the height and/or lateral guide elements 30, 31and drive rollers 37 and pressing elements 36 of the displacement drives13, 14 are disposed on a guide carriage which can be displaced along aguide mechanism transversely to the aisle direction—indicated by doublearrow 15- and transversely to the runner rails 11, 12. To this end, theguide carriage is designed so that it can be displaced relative to thehousing 38 of the displacement drive 13, 14.

[0087] In another embodiment of the coupling connection 27, notillustrated, it is provided in the form of an actuatable drive, inparticular a threaded spindle, which is displaceably affixed to thearticulation axes 42 a, 42 b.

[0088]FIG. 4 is a partial section illustrating a part region of the mast2 with the mast foot 5 bearing the bottom bogie assembly 7 and a runner46 co-operating with the bogie assembly 7, as well as the bottom guidetrack and the runner rail 11 constituting it. The bogie assembly 7 hasat least one height guide element 20, in particular the height guideroller, which rotates about the rotation axis 21 extending transverselyto the longitudinal extension of the runner rail 11 and rolls along thehorizontal guide track part 19 of the runner rail 11, and the runner 46,which is mounted so as to be pivotable about the rotation axis 21 of theheight guide elements 20. The runner 46 essentially engages round therunner rail 11, being substantially U-shaped in cross section, and haslateral guide elements 24 on its legs 47 extending substantiallyparallel with the web and mutually spaced apart from the latter, whichare rotatable about rotation axes 25 extending parallel with the guidetrack parts 10 of the web 17. Disposed on a base 48 of the runner 46facing the top belt 18 of the runner rail 11 is at least one wiper bar49 which rides on the guide track parts 19. The substantiallyplate-shaped wiper bar 49, the contour of which is adapted to match thetop belt 18, is designed to be displaceable about its transverse medianaxis extending parallel with the rotation axis 21 of the height guideroller against the action of elastic return elements arranged on eitherside of the transverse median axis. The wiper bar 49 therefore acts as asort of dolly, which always sits with its full surface essentially flatagainst the guide track part 19 of the runner rail 11 irrespective ofthe operating position of the mast 2. The elastic return elements 50,which are provided in the form of spring systems, for example, are heldin position between the runner bar 49 and the base 48 of the runner 46by means of pin-type guide elements 51. Another advantage of providingthe wiper bar 49 primarily resides in the fact that if the mast 2 ismoved into a crooked position by the return elements 50 spaced apartfrom one another about the transverse median axis, an equilibrium offorces occurs in the return elements 50, which are spaced apart from oneanother in the longitudinal direction, and the resultant reaction forcesof the return elements 50 move the runner into a pre-definable, inparticular horizontal position, thereby orienting the lateral guideelements 24 in such a way that the rotation axes 25 are disposedperpendicular to the longitudinal extension of the runner rail 11. Inthis particular embodiment, two pairs of return elements 50 co-operatewith the wiper bar 49. Even if the mast 2 assumes a crooked position,the fact that the runner 46 bearing the lateral guide elements 24 isautomatically oriented avoids generating additional friction-inducedwear, which would otherwise occur as a result of such a crooked positionor contact with the lateral guide elements 24. The wiper bar 49 ispreferably made from a wear-resistant plastic, such aspolytetrafluoroethylene, polyamide.

[0089] Naturally, the return elements 50 could also be provided in theform of mechanically and/or electrically and/or hydraulically and/orpneumatically operated means.

[0090] For the sake of simplicity, the structural design and operatingmode of the runner 46 will be described in connection with the region ofthe mast foot 5 only. Clearly, the mast head 6 and the top bogieassembly 8 could also be provided with the same type of runner 46.However, this is not illustrated as such.

[0091]FIG. 5 illustrates a side view of a lift mechanism 52 of the rackserving device 1, which constitutes a separate invention in its ownright. With a view to keeping the description simple, the diagram showsonly the bogie assemblies 7, 8 on the mast foot 5 and mast head 6, whichare guided on guide track parts 10, 19 of the bottom and top guidetracks and the runner rails 11, 12 forming them. The structure andoperating mode of the bogie assemblies 7, 8 described above in respectof FIGS. 1 to 4 also apply here. The sled-type lift carriage 3incorporating load-bearing means 4, displaceable in the height directionof the mast 2, is guided by means of a guide mechanism with at leastone, preferably two height and/or lateral guide elements 53 on at leastone guide track 54 of the mast 2 and is displaceable essentiallyvertically along the guide track 54 by means of a drive mechanism 55.The lift carriage 3 also has load-bearing means 4 extending out abovethe guide track 54. At least one linkage point 56 of the drive mechanism55 on the lift carriage 3 is arranged transversely to the vertical guidetrack 54, for example offset in the direction of the load-bearing means4. As may also be seen from this drawing, at least one other linkagepoint 58 is provided on the lift carriage 3, arranged transversely tothe guide track 54, offset in the direction of the mast 2, and at adistance 57 from the at least one first linkage point 56.

[0092] The drive mechanism 55 has at least one drive element 60, whichcan be driven by a lift motor 5 connected to the lift carriage 3, whichis displaceable by means of the belt-type drive element 60 at the firstand other linkage point 56, 58. The belt-type drive element 60 is anendless traction belt, in particular a cogged belt. The lift motor 59,which has a drive element, is arranged on the mast 2, preferably in theregion of the mast foot 5 or on the bottom bogie assembly 7. Lyingopposite it in the region of the mast head 6 is at least one drivemember for the drive element 60 circulated about it. The distance 57, asmeasured horizontally, is variable and is defined by selecting differentdiameters of the drive member and drive element. By preference, the masthead 6 or the support frame 39 has two output elements, in particularpulley rollers, spaced apart from one another in the aisle directionindicated by double arrow 15—about which the drive element 60 iscirculated during a displacement of the lift carriage 3. End regions ofthe drive element 60 are connected directly to the lift carriage 3 so asto be immobilised by fixing mechanisms directly in the linkage points56, 58.

[0093] If several drive elements 60 extending parallel with one anotherare used, their end regions are articulatingly linked by means ofanchoring legs on the lift carriage 3, although these are notillustrated. This being the case, an anchoring leg, which is mounted soas to pivot on an articulating joint about an axis extendingtransversely to the direction of displacement—indicated by double arrow61—is provided at each of the linkage points 56, 58 and at least twofinite drive elements 60 are connected to the two anchoring legs attheir end regions on either side of the articulating joint.

[0094] Within the scope of the invention, the rack serving device 1proposed by the invention may specifically be operated in adeep-freezing or cooling area or at low temperatures, in which case thedrive element 60 co-operates with at least one system 62 for regulatinga temperature of the drive element 60. The system 62 is preferablymounted on the rear face of the mast 2 disposed along a part of thelength of the drive element 60. In order to regulate the temperature,energy is delivered to the drive element 60 by means which may becontactless or involve contacts or involve physical contact. Thebelt-type drive element 60 is fed past or fed through at least oneenergy field 63, the energy field 63 being provided in the form of amechanical or magnetic or electrical or electromagnetic field. Theelectromagnetic field is preferably provided as a medium-frequency orhigh-frequency alternating field. The system 62 has at least oneinduction device 64 to which an alternating current is applied or atleast one microwave generator to create an energy field 63 which isactively linked to the drive element 60. The system 62, whichessentially extends at least around the drive element 60 and theinduction device 64 incorporates the primary induction coil, and currentor voltage in a secondary induction coil is provided via strengtheningsupports of the drive element 60, although these are not illustrated.The voltage induced in the strengthening supports, in particular steelwires, on the one hand enables the temperature of the drive element 60to be regulated and on the other provides a status-monitoring system, inparticular for monitoring the load capacity of the strengtheningsupports. The strengthening supports therefore form at least one loop ofelectrically conductive material, extending across at least a part ofthe length of the drive element 60. Naturally, it would also be possibleto provide the loop in the form of an electrically conductive film, inparticular copper film, a film of steel alloy or spring steel, extendingacross at least the length and at least a part of the width of the driveelement 60. The strengthening supports are made from electricallyconductive materials known from the prior art, such as aramide or steeland glass fibres.

[0095] The system 62 is mounted externally to the drive element 60,either stationary at a distance from it or so as to be displaceable inthe drive element and/or along the drive element 60. In order toregulate the temperature, at least one measuring means is provided in ordirectly adjacent to the drive element 60 to detect the temperature ofthe drive element 60, in particular a strain gauge, thermocouple. Theactual temperature values detected by the measuring means are forwardedto a control system in the control cabinet 16 or to a central controlsystem, where appropriate control algorithms are provided in order toregulate and adapt the actual value to a pre-settable desired value forthe temperature of the drive element 60.

[0096] At least the fixed induction coil, to which alternating currentis applied, is provided in the form of a network-side primary coil andinduces current or voltage in the strengthening supports acting as thesecondary coil by means of the changing magnetic flow in at least oneelectrically conductive material. The relative displacement of the driveelement 60 in respect of the system 62 and hence in respect of theenergy field 63, in particular the electromagnetic field, enables auniform, pre-definable temperature of +15° C., for example, to be setand maintained across the entire length and cross section of the driveelement at an ambient temperature of −10° C., for example. As a resultof the invention, it is now possible to warm or heat the drive element 2to a predefined minimum temperature during the relative displacementbetween it and the at least one system 62. The frequency rangeprimarily, and optionally the current intensity, may serve as variablesfor regulating the primary side induction coil to which alternatingcurrent is applied. The electromagnetic energy field 63 is generated byoperating the induction coil in the medium-frequency or high-frequencyrange, in which case the frequency range is between 1 kHz and 150 kHz,for example 50 kHz.

[0097] By applying the energy field 63 intermittently or to at leastcertain regions of the drive element 60 and the electrically conductivestrengthening supports, heat is generated in at least a part region ofthe drive element 60 due to the power loss, depending in particular onthe frequency of the primary-side induction coil. The control system ofthe warehouse management system is configured so that the frequency isset depending on the circulation speed of the drive element 60 and/orthe temperature to which the drive element 60 is subjected and/or afixed actual value for the temperature determined by a measuring means,for example a thermocouple, pyrometer, by which the temperature iscontactlessly detected. The drive element 60 may be equipped withmeasuring means disposed at a distance from one another in the directionof its length for intermittently or locally detecting the actual valueof the temperature in different regions of the drive element 60. Theseindividually detected actual values of the temperature are forwarded tothe control system, where they serve as a basis for calculating thearithmetic mean value of the temperature in order to control whateverparameter is used, such as the frequency of the induction coil or amicrowave generator, the heat output contactlessly transmitted by thesystem 62 or the current intensity of the current flowing through thestrengthening supports. Sensor systems known from the prior art may beused to set these individual parameters, such as temperature sensors,strain gauges, thermocouples. The sensor systems for detecting ambientinfluences, such as air humidity, ambient temperature, etc., aredisposed in the surrounding area, for example in the room in which therack serving device 1 is installed, and are connected to the controlsystem to permit data transmission. Measuring means are provided in oron the drive element 60 in order to determine the actual value of itstemperature. The actual temperature value of the drive element 60 may bedetected in the running layer and/or the facing layer and/or thetraction layer and each of the individual measurement values forwardedto the control system will be used as a basis for determining a controlvariable for the parameter. Alternatively, the actual temperature valuemay also be detected by contactless means. Applying regulated heat andmaintaining a set temperature permits a dynamic displacement of the liftcarriage 3 and the load-bearing means 4, even at low temperatures, forexample in the range of between 0° C. and −80° C.

[0098] The system 62 could also be provided in the form of a heatingelement, such as filaments or a radiator element such as a heatexchanger, blowers, in order to create a thermal energy field 63 whichacts on the drive element 60. Clearly, the system 62 could also beprovided on or in the lift carriage or alternatively by means of it.

[0099] In another embodiment, although this is not illustrated, a directvoltage is applied to clamp contacts connected to the strengtheningsupports so that the strengthening supports essentially act as a heatingelement, thereby enabling the pre-definable temperature to be set and/ormaintained in the drive element 60.

[0100] As regards the various embodiments which may be used for thesystem 62 for regulating the temperature, the operating modes of thedifferent systems 62, the method of regulating the temperature of thedrive element 60 and the various structural designs of the drive elementare described in detail in Austrian patent application A 822/2001, whichis specifically included in this disclosure. For this reason, moredetailed explanations will not be given in this disclosure.

[0101]FIG. 6 illustrates a part region of the mast 2 with the bogieassembly 7 disposed at the mast foot 5, which is supported and guided onthe bottom guide track and the runner rail 11 formed by it by means ofheight and lateral guide elements 20, 24. The housing-type surroundingframe 22 of the bogie assembly 7 has at least one anti-lift system 65 ona face directed towards the runner rail 11, disposed between the runnerrail 11, in particular a bottom belt, and the bogie assembly 7, in orderto prevent the mast 2 from tipping over should it assume an inadmissiblecrooked position. The bracket-type anti-lift system 65 engaging round atleast certain regions of the runner rail 11 is secured to the bogieassembly 7 by its base so as to be immobilised, and free bracket endregions 66 are provided with support elements 67, such as skids, wheels.When the mast 2 is oriented in the vertical direction, the supportelements are disposed at a distance from the guide track parts 32,whereas if the mast 2 assumes an inclined position that is essentiallynot permissible, the support elements 67 move into abutment on the guidetrack parts 32 and hold the mast 2 in a secured position.

[0102] As illustrated in FIG. 2, the to bogie assembly 8 is also fittedwith at least one anti-lift system 65, which is arranged between the topguide track or the top runner rail 12 formed by it, in particular a topbelt, and the top bogie assembly 8. The top anti-lift system 65 isintended to prevent the mast 2 from lurching over should it assume acrooked position and holds it secure in its crooked position. Asdescribed above, the anti-lift system 65 has support elements 67 in thebracket end regions 66.

[0103]FIG. 7 shows a side view of the rack serving device 1, which isdisplaceable along the bottom and top guide track or runner rail 11, 12,guided in the height direction and at the side, the individual units ofwhich, such as bogie assemblies 7, 8, adjusting mechanisms ordisplacement drives 13, 14 etc., are the same as those described inrespect of the earlier drawings. As may be seen from this diagram, atleast one ladder 68 which is displaceable along at least one, preferablythe top runner rail 12 and is guided in the height direction and at theside, can be moved into position relative to the rack serving device 1for maintenance purposes and for repair work. The ladder 68 ispreferably length-adjustable and is supported and secured by means of anextractable or pivoting support apparatus 69 on a floor 70 of abuilding. In order to provide height and lateral guidance, the ladder 68has at least one ladder bogie assembly 71 at its top end with height andlateral guide elements. Although not illustrated, it would naturallyalso be possible for the ladder to extend across the entire height ofthe mast 2, in which case it could by supported on the top and bottomrunner rail 11, 12 and guided along this runner rail 11, 12 in theheight direction and to the side by means of both a bottom and topladder bogie assembly 71. During operation of the rack serving device 1,the ladder 68 is stowed away in a stand-by region externally to apre-definable working space of the rack serving device 1, the stand-byposition of the ladder 68 being monitored by means of at least onesensor system provided in the stand-by region specifically for thispurpose. When the rack serving device 1 is switched off, the ladder 68can be brought alongside the rack serving device 1 and can be releasablylocked in this position by means of mechanical and/or electric and/orpneumatic and/or hydraulic locking elements so that it is docked on therack serving device 1 or secured in position relative to the floor 70and/or the runner rail 11; 12 by means of brake and locking mechanismsprovided on the ladder 68. The ladder 68 can be manually displaced alongthe runner rail 11; 12 or automatically or remotely controlled byproviding at least one drive element on at least one of the ladder bogieassemblies 71. Ladders 68 of this type are already generally known fromthe prior art and are provided with all the safety features needed forthis application.

[0104]FIG. 8 is a highly simplified, schematic diagram illustrating aside view of an example of a system in which a plurality of rack servingdevices 1 are combined to form one assembled rack serving unit 72. Therack serving unit 72 is made up of several rack serving devices 1arranged one after the other and actively connected to one another. Therack serving devices 1 spaced at a distance apart from one another inthe aisle direction—indicated by double arrow 15—are connected to oneanother, preferably so that they can be released, by means of supportframes 73 provided between the masts 2, in particular their bottom andtop bogie assemblies 7, 8. The support frames 73 are schematicallyindicated by dotted-dashed lines. Two rack serving devices 1 areexpediently arranged on the guide tracks or runner rails 11, 12 in sucha way that their load-bearing means 4 are directed towards one another,which means that they are able to accommodate a load 9 with a largesurface area, such as a pallet. The two rack serving devices 1 areguided on the guide track parts 10, 19, 32 of the guide tracks or runnerrails 11, 12 by their bogie assemblies 7, 8 and at least one of the rackserving devices 1 is provided with at least one coupling part 28 fortransmitting or applying a forward motion to the rack serving unit 72.Consequently, the rack serving unit 72 has only one, preferably thebottom, displacement drive 13. As may be seen from this drawing, therack serving unit 72 expediently has both displacement drives 13, 14.Naturally it would be possible to align any number of rack servingdevices 1, releasably connected to one another, to form a large rackserving unit 72.

[0105] Naturally, the rack serving devices 1 could also be disposed sothat their load-bearing means 4 extend in opposite directions from oneanother.

[0106] In another variant, which is not illustrated, several rackserving devices 1 are held together at a pre-definable distance from oneanother and/or are displaced at a pre-definable distance from oneanother and an automatic control system activating the displacementdrives 13, 14 is provided in order to control the unit on the basis of aprogramme. Naturally, it would also be possible for several rack servingdevices 1 to be moved freely and simultaneously, remotely controlled bythe control system, in which case a minimum distance will be maintainedbetween the rack serving devices 1 in order to avoid collisions.

[0107] As illustrated in FIG. 1, the rack serving device 1 can be fittedwith at last one position detection system 74, which is mounted on themast 2 and/or on the bogie assembly 7, 8 and/or on the displacementdrive 13, 14 and/or on the load-bearing means 4, for example. Such aposition detection system 74 may be a navigation device, in particularGPS, consisting of a transmitter and/or receiver unit 75 on the rackserving device 1, and a transmitter and/or receiver unit, notillustrated, in a pre-definable working area. The advantage of using aposition detection system 74 of this type is that a position of the rackserving device 1 and/or the position and/or a distance of theload-bearing means 4 relative to a racking system and/or a rack shelfcan be detected on the basis of the associated X-Y coordinates. Theseco-ordinates, or data such as the speed curve, can be forwarded to thecontrol system in the control cabinet 16 and/or to a central controlsystem of a warehouse administration computer for further processingand/or output.

[0108] At least one image-processing element, in particular a CCDcamera, may also be mounted on one or more points of the rack servingdevice 1, such as in the region of the lift carriage 3 and/or the bogieassemblies 7, 8 and/or the displacement drives 13, 14, for the purposeof monitoring various states, such as wear on the bogie assemblies 7, 8and/or the displacement drives 13, 14 or for monitoring the process ofstoring and retrieving the loads 9 in the rack shelves, etc. Thedetected data and images are also forwarded to the control system in thecontrol cabinet 16 and/or to a central control system and evaluated.This will enable maintenance and repair data or diagnoses to beestablished. Commands and/or data and/or signals are transmitted bymeans of lines, preferably run substantially through the interior of themast 2, and/or by contactless means, such as an ultrasound or infraredtransmission, to the control system.

[0109] Another function of the control system is to maintain the mast inits substantially vertical position, for which purpose highly dynamictracking controls of the drive motors of the displacement drives 13, 14are used. To this end, the bottom and top drive motors havesubstantially the same power rating so that any horizontal deviation ofthe mast foot 5 and mast head 6 from their position can be kept as lowas possible under all operating and load conditions. The function of thetracking controls is to keep the rack serving device 1 with the mast ina preferably vertical position under all operating conditions.

[0110] To this end, a reference line is defined by two points on abearing surface of the load-bearing means 4, which is horizontallyoriented when the mast 2 is in the vertical position. If the mast 2deviates from its vertical position, the inclination of the referenceline changes and this is detected by means of at least one sensor system76 disposed on the load-bearing means 4, such as a levelling device forexample. The change in inclination is transmitted to the control system,where appropriate control algorithms compare the constantly detectedactual value with a pre-definable desired value for the inclination andadapt it to the desired value by activating the drive system 33 of thebottom and/or top displacement drive 13; 14. The driving torque of thetop displacement drive 14 is changed, preferably until the load-bearingmeans 4 is horizontally aligned. Levelling the load-bearing means 4 alsoreturns the mast 2 to a substantially vertical orientation because theload-bearing means 4 is mounted on the mast 2 in such a way that it canbe guided in terms of its height and at the side virtually without anyclearance by means of the lift carriage.

[0111] The sensor system 76 may also serve as the position detectionsystem 74. Alternatively, it would also be possible to detect the actualvalues for the respective travel of the mast foot 5 and mast head 6 onthe bottom and top runner rail 11, 12. The control system constantlycompares the travel actual values with the respective pre-set desiredvalues for the travel. If there is a deviation from the travel desiredvalues, the actual values are automatically adapted to the desiredvalues for this travel by adjusting the driving torque of a displacementdrive 13; 14, preferably the top displacement drive 14.

[0112] In order to ensure that slip between the drive rollers 37 and therunner rails 11, 12 is kept low, even when handling heavy loads 9, aweight measuring system may be provided on the lift carriage 3 orload-bearing means 4, in particular a weighing cell, force measuringunit, etc., by means of which the weight of the load 9 is determined, sothat an automatic control unit can adjust a variable contact force ofthe drive rollers 37 and/or contact elements 36 of the displacementdrives 13, 14 and/or the inclination of the load-bearing means 4 isadjusted by changing the position of the displacement drives 13, 14disposed one above the other depending on the currently acting torque.The contact force and the inclination of the load-bearing means 4 may beadjusted by means of the mechanical and/or electromechanical couplingconnection 27 constituting the coupling mechanism 29, in particularactuator elements, such as a threaded spindle, for example.

[0113]FIGS. 9 and 12, which will be described together, illustratedifferent views of the mast 2 for the rack serving device 1, which isnot illustrated in this drawing. By preference, the lift mechanism 52and the rack serving device 1 of the mast 2 are the same as the rackserving device 1 and lift mechanism 52 described in connection with thediagrams given in FIGS. 1-8.

[0114] The design and manufacture of this mast 2 does not depend on thedesign of the lift mechanism 52 and the rack serving device 1 and may beconstrued as the object of a separate, independent patent.

[0115] Above all, this independent embodiment of the mast 2 achieves thepreferably independent objective of providing a mast 2 for the rackserving device 1 which is specifically made and designed to improve thecapacity to withstand prevailing static and dynamic stress and can alsobe used for both high static and/or dynamic loads.

[0116] The mast 2 is made from two assembled substantially half-shellelongate sections 80 with a substantially C-shaped cross section. Awidth 81 of a base 82 of the elongate sections 80 is bigger than aheight 83, 84 of the legs 85, which extend essentially perpendicularthereto. As may be seen from FIG. 9, the width 81 is longer than themaximum height 83 of the elongate sections 80. The mast 2, which is madefrom two elongate sections 80 joined to one another to form a hollowsection, is cruciform in cross section and has outwardly directed,substantially U-shaped protuberances 86 on oppositely lying faces,extending in the longitudinal direction of the mast 2 with sectionstrips standing proud of the base 82 of the elongate sections 80. Eachof the U-shaped protuberances 86 extending along the entire mast length,in particular the section strips 87, forms a running surface 89 inplanes extending perpendicular to a plane of longitudinal symmetry 88for the running wheels 90 of the lift carriage 3 forming lateral guideelements, which can be displaced on the mast 2, although this is notillustrated in this drawing. The protuberances 86 therefore form guidetracks 54 a on oppositely lying width faces of the mast 2 in thelongitudinal direction for the running wheels 90 forming the lateralguide elements 53.

[0117] Each of the substantially C-shaped elongate sections 80 forms asubstantially L-shaped projection 91 at one of its free ends, which, ona first face remote from the plane of symmetry 88, forms a runningsurface for the lateral guide element 53 or running wheel 90 of the liftcarriage 3 displaced and guided on the mast 2, and another surfacedirected towards the plane of longitudinal symmetry 88 which serves as asupport and/or joint surface 93. When the elongate sections 80 areassembled, the two projections 91 form the other guide track 54 b andrunning surfaces 92 disposed at a right angle to the guide tracks 54 aon a slim face of the mast 2 and extending along the entire mast length.The running surfaces 92 of the projections 91 extending in thelongitudinal direction of the mast 2 and standing proud of the legs 85of the elongate section 80 extend parallel with one another and parallelwith the plane of longitudinal symmetry 88. At their free ends, thesubstantially L-shaped projections 91 have upstanding longitudinal edges94 forming the support and/or joint surfaces 93 extending parallel withthe plane of longitudinal symmetry 88, which butt with one another inthe connecting region 95 to form a hollow fillet between the twoelongate sections 80 to be joined to one another.

[0118] At their free ends lying opposite the projections 91, the legs 85of the elongate sections 80 have longitudinal edges 94 disposedsubstantially parallel with the plane of longitudinal symmetry 88 andforming the support and/or joint surfaces 93, which butt with oneanother in the joint region 96 to form a hollow fillet between the twoelongate sections 80 to be joined to one another. The join between theelongate sections 80 in the two joint regions 95, 96 along the hollowfillet is preferably provided in the form of a welded seam 97 extendingalong the entire mast length.

[0119] The section parts 98 of the legs 85 of the elongate sections 80between the protuberances 86 and the projections 91 extend at an angletowards one another in the direction of the width 81 and taper thefarther away they are from the protuberances 86 in the direction of theprojections 91 up to the section parts 99 disposed perpendicular to theplane of longitudinal symmetry 88, where they are adjoined by therunning section strips 87 of the projections 91 disposed perpendicularto the section parts 99 and provided with the running surfaces 92. Anangle 100 subtended by the section parts 98, 99 is between 90° and 160°,in particular between 110° and 140°, for example 135°. As may also beseen from FIG. 9, the base 82 of the elongate sections 80 extends at anincline relative to the plane of longitudinal symmetry 88, tapering thefarther away they are from the protuberances 86 in the direction of thelegs 85 extending perpendicular to the plane of longitudinal symmetry88. The angle 101 between the base 82 of the two elongate sections 80 isbetween 5° and 25°, in particular between 8° and 18°, for example 10°.

[0120] The elongate sections 80 are of a symmetrical design and have awall thickness 102 which is substantially constant throughout theircross section, which is between 3 mm and 6 mm, for example 4 mm. Abridging width 103 of the abutting longitudinal edges 94 of the twoelongate sections 80 extending parallel with one another in the sameplane preferably corresponds to at least three times the wall thickness102 and is, for example, between 9 mm and 18 mm, for example 12 mm.Between the base 82 and the leg 85 is a rounded region with a radius 104of between 40 mm and 80 mm, in particular 50 mm and 70 mm, for example60 mm.

[0121] On their base 82, the elongate sections 80 have slot-shapedcutouts 105 disposed in a row one after the other in the mastlongitudinal direction, the primary purpose of which is to facilitatethe mounting and running of power lines inside the mast 2 for example,because these cutouts 105 provide access to the interior of the mast 2using a tool.

[0122] In order to satisfy the requirements of being able to withstandhigh static and dynamic stress, such as torsion, bending stress, etc.,even if the wall thickness 102 is slim, the open end of thesubstantially U-shaped protuberances 86 facing the interior of the mast4 is closed off respectively with at least one strip-type stiffeningelement 106 overlapping with the lateral abutting regions of theprotuberances 86, as described in connection with FIGS. 11 and 12, orthe abutting regions are joined to one another by at least onestiffening element 106. The stiffening element 106 has a first side edge107 extending parallel with and sitting flat against the leg 85, inparticular with the section part 98 of the elongate sections 80, andanother side edge 108 extending parallel with the base 82 and sittingflat against the elongate sections 80, and optionally at least twolaterally protruding positioning projections 109 on one of the sideedges 108 spaced at a distance apart from one another in thelongitudinal direction of the stiffening element 106, extending parallelwith the one section strip 87 and sitting flat against it.

[0123] The stiffening elements 106 expediently extend along the entiremast length and are joined in a positive fit by means of two continuousweld seams 97 extending between the side edges 107, 108 and the legs 85as well as between the base 82 of the elongate sections 80 and theelongate sections 80. Alternatively, it would also be possible toprovide strip-like stiffening elements 106 immediately one after theother along the entire mast length, either abutting with one another orseparated from one another by a vertical distance, each of which isjoined along the length of the stiffening element 106 by continuouslyextending weld seams between the side edges 107, 108 and the legs 85 andbetween the base 82 and the elongate sections 80.

[0124] Naturally, it would also be possible for the join between theelongate sections 80 in the joint regions 95, 96 and/or in the jointregions between the stiffening elements 106 and the elongate sections 80to be provided in several sections in the form of mutually separate weldseams. However, the embodiment with continuous weld seams 97 along theentire mast length in the joint regions 95, 96 and between thestiffening elements 106 and the elongate sections 80 is the preferredvariant.

[0125] As schematically indicated by broken lines in FIG. 9, thestiffening elements 106 may also be adapted to match the protuberances86 with the substantially U-shaped cross section, in which case theywill also have a substantially U-shaped cross section. This embodimentfurther increases the capacity to withstand mechanical stress becausethe legs and/or the base of the stiffening elements 106 areadvantageously supported on at least certain regions of the internalcontour of the protuberances 86. Alternatively, as also indicated bybroken lines in FIG. 9, at least one strip-type stiffening element 106may also be provided between the L-shaped projections 91, joined to oneanother to form a substantially U-shaped guide track 54 b on an openface of the guide track 54 b directed towards the protuberances 86,overlapping with the side regions adjoining the projections in thelongitudinal direction of the mast 2. The at least one stiffeningelement 106 is permanently joined by means of a connecting element, e.g.a screw connection, a welded joint, a rivet joint, etc., to the two legs85 of the elongate sections 80. Naturally, it would also be possible toprovide several stiffening elements 106 one after the other in thelongitudinal direction of the mast 2, in which case each of thestiffening elements 106 would be joined by means of the joining element106 to the elongate sections 80 and/or have more or less the samecross-sectional shape as the guide track 54 b. Providing this additionalstiffening element 106 will enable the mast 2 to cope with high loads inparticular.

[0126] A thickness 110 of the stiffening elements 106 preferablycorresponds to the wall thickness 102. In order to increase the capacityof the mast 2 to withstand mechanical stress, the stiffening elements106 could also have a thickness 110 that is a multiple of the wallthickness 102, for example twofold. Cutouts 111 could also be providedin the stiffening element 106 to facilitate assembly and/or the runningof power cables, for example, as described in more detail above, inwhich case these are arranged in a row one after the other in thelongitudinal direction of the stiffening element 106.

[0127] The elongate sections 80 illustrated in the various drawings aremade from a flat piece cut from sheet steel made by a rolling process oran internal high-pressure forming process and provided with a zinccoating with a thickness of for example 5 μm to 20 μm, for example 10μm, on their internal and/or external surfaces. The two elongatesections 80 are firmly joined to one another by means of a metal inertgas welding process (MIG welding) or an arc welding process. The weldmay contain an additional material in the form of an added substancewith a copper base, e.g. CuSi3MnAl. The elongate sections 80 are madefrom steel, in particular a fine-grained construction steel.

[0128] The surprising advantage of welding is that only a low amount ofheat is introduced during the welding process, which means that the zinclayer is essentially hardly reduced at all and the slight burning of thezinc which occurs at the side of the weld seams 97 has virtually noeffect on corrosion resistance because the cathodic distance protectingeffect is also maintained in the joint regions 95, 96 between theelongate sections 80 and between the stiffening elements 106 and theelongate sections 80.

[0129] Another advantage is the fact that it is a simple matter to makethe mast 2 from the two elongate sections 80 because the elongatesections 80, made by the preferred rolling process, are already made totheir ultimate dimensions, after which each of the elongate sections 80is placed in a device and fixed in position. The stiffening elements 106are then placed on the elongate section 80 in the region of theprotuberances 86 and positioned by means of the positioning projections109 relative to the protuberance 86 in the direction extending parallelwith the plane of longitudinal symmetry 88 and by means of the inclinedlongitudinal edge 107 extending parallel with the section part 98 in thedirection extending perpendicular to the plane of longitudinal symmetry88 so that they can then be positively joined to the elongate sections80 in the regions adjoining the protuberances 86. The two elongatesection 80 are then aligned in their desired relative position andplaced one against the other by their mutually facing support and/orjoint surfaces 93 extending parallel with one another in the same planeand parallel with the plane of longitudinal symmetry 88 and welded toone another at their hollow fillet formed by the mutually abuttinglongitudinal edges 94 of the two elongate sections 80. After joining thetwo elongate sections 80, at least one strip-shaped stiffening element106 can then be optionally placed in position between the projections 91on an open side of the guide track 54 b facing the protuberances 86 andjoined to the elongate sections 80 from the exterior, by means of blindrivets, screws, a weld seam, for example.

[0130] It is of particular advantage that the manufacturing tolerancesof the elongate sections 80 made in a single piece from a flat cuttingin a rolling process, are compensated in the joint regions 95, 96between the two elongate sections 80 and between the stiffening elements106 and the elongate sections 80 by the added material, the solidifiedweld seam 97 being of a higher strength than the elongate sections 80.

[0131] For the sake of good order, it should finally be pointed out thatin order to provide a clearer understanding of the structure of the rackserving device 1, it and its constituent parts are illustrated to acertain extent out of scale and/or on an enlarged scale and/or on areduced scale.

[0132] The underlying objectives to the solutions proposed by theinvention may be found in the description.

[0133] Above all, the individual embodiments of the inventionillustrated in FIGS. 1, 2, 3; 4; 5; 6; 7; 8; 9, 10, 11, 12 may beconstrued as independent solutions proposed by the invention in theirown right. The associated objectives and solutions may be found in thedetailed descriptions of these drawings. List of reference numbers  1Rack serving device  2 Mast  3 Lift carriage  4 Load-bearing means  5Mast foot  6 Mast head  7 Bogie assembly (bottom)  8 Bogie assembly(top)  9 Load 10 Guide track part 11 Runner rail (bottom) 12 Runner rail(top) 13 Displacement drive (bottom) 14 Displacement drive (top) 15Double arrow 16 Control cabinet 17 Web 18 Top belt 19 Guide track part20 Height guide element 21 Rotations axis 22 Surrounding frame 23 Sidewall 24 Lateral guide element 25 Rotation axis 26 Rear wall 27 Couplingconnection 28 Coupling part 29 Coupling mechanism 30 Height guideelement 31 Lateral guide element 32 Guide track part 33 Drive system 34Axis 35 Rotations axis 36 Contact element 37 Drive roller 38 Housing 39Support frame 40 Coupling part 41 Jaw part  42a Articulation axis  42bArticulation axis 43 Guide element 44 Longitudinal guide 45 Guide track46 Runner 47 Leg 48 Base 49 Wiper bar 50 Return element 51 Guide element52 Lift mechanism 53 Height and lateral guide element  54a Guide track 54b Guide track 55 Drive mechanism 56 Linkage point 57 Distance 58Linkage point 59 Lift motor 60 Drive element 61 Double arrow 62 System63 Energy field 64 Induction system 65 Anti-lift system 66 Bracket endregion 67 Support element 68 Ladder 69 Support apparatus 70 Floor 71Ladder bogie assembly 72 Rack serving unit 73 Support frame 74 Positiondetection system 75 Transmitter and/receiver unit 76 Sensor system 77 7879 80 Elongate section 81 Width 82 Base 83 Height 84 Height 85 Leg 86Protuberance 87 Section strips 88 Plane of longitudinal symmetry 89Running surface 90 Running wheel 91 Projection 92 Running surface 93Support and/or joint surface 94 Longitudinal edge 95 Joint region 96Joint region 97 Weld seam 98 Section part 99 Section part 100  Angle101  Angle 102  Wall thickness 103  Bridging width 104  Radius 105 Cutout 106  Stiffening element 107  Side edge 108  Side edge 109 Positioning projection 110  Thickness 111  Cutout

1-85 (CANCELED)
 86. Lift mechanism (52) for a rack serving device (1)which can be used in particular in a deep-freezing and cooling region,with a mast (2) and a sled-type lift carriage (3) mounted on the mast(2), which is essentially vertically displaceable in the heightdirection of the mast (2) by means of at least one belt-type driveelement (60), in particular a traction means, the drive element (60)being connected to the lift carriage (3), characterised in that thedrive element (60) co-operates with at least one energy deliveringsystem (62) in order to control the temperature of the drive element(60) and at least one measuring means assigned to the drive element (60)for detecting the actual value of the temperature of the drive element(60), and the at least one measuring means is connected to a controlsystem controlling the system (62).
 87. Lift mechanism as claimed inclaim 86, wherein the drive system (60), in particular the tractionmeans, is endless or finite and is guided by at least one drive elementdisposed on the mast (2) coupled with a lift motor (59) via at least onedrive element disposed at the mast head (6).
 88. Lift mechanism asclaimed in claim 86, wherein the system (62) delivers energy to thedrive element (60) without contact or involving the use of contacts orby making contact, and is disposed at a short distance from the driveelement (60) or is wired to the drive element (60).
 89. Lift mechanismas claimed in claim 86, wherein the system (62) extends across a part ofa length of the drive element (60) in order to heat at least certainregions of the displaceable drive element (60).
 90. Lift mechanism asclaimed in claim 86, wherein the drive element (60) is moved alongsideat least one or guided through at least one energy field (63) and theenergy field (63) is a mechanical or magnetic or electric orelectromagnetic field.
 91. Lift mechanism a claimed in claim 90, whereinthe electromagnetic field is preferably a medium- or high-frequencyalternating field.
 92. Lift mechanism as claimed in claim 86, whereinthe system (62) comprises at least one induction system (64) or at leastone microwave generator for generating an energy field (63) activelyconnected to the drive element (60).
 93. Lift mechanism as claimed inclaim 92, wherein the induction system (64) forms a primary inductioncoil which can be energised with alternating current, and at least oneloop of electrically conductive material actively connected to it anddisposed in or on the drive element (60) forms a secondary coil. 94.Lift mechanism as claimed in claim 86, wherein the system (62) is aheating element such as a filament, or a heat radiator such as a heatexchanger, blower, to generate a thermal energy field (63) activelyconnected to the drive element (60).
 95. Lift mechanism as claimed inclaim 86, wherein the system (62) is disposed on or in the lift carriage(3) or is constituted by the latter.
 96. Lift mechanism as claimed inclaim 93, wherein the loop comprises at least one strengthening supportextending along the length of the drive element (60).
 97. Lift mechanismas claimed in claim 93, wherein the loop comprises at least oneelectrically conductive film, in particular a copper film, a film ofsteel alloy or spring steel, extending along the length and at least apart of a width of the drive element (60).
 98. Lift mechanism as claimedin claim 86, wherein the system (62) is fixedly positioned externally tothe drive element (60) or is disposed so that it can be displaced in ortowards the drive element (60) or the loop.
 99. Lift mechanism asclaimed in claim 86, wherein at least one measuring means for detectingthe temperature is disposed in or directly on the drive element (60), inparticular a strain gauge, a thermocouple, and the measuring means isconnected to the control system.
 100. Lift mechanism as claimed in claim86, wherein the at least one measuring means, in particular a pyrometer,is disposed separately from the drive element (60) and the actual valueof the temperature of the drive element (60) can be detected withoutcontact and forwarded to the control system.
 101. Lift mechanism asclaimed in claim 86, wherein the control system contains a controlalgorithm for regulating the temperature of the drive element (60). 102.Rack serving device (1) with a lift carriage (3) incorporatingload-bearing means (4), whereby the mast (2) is guided on bottom and toptracks by means of bogie assemblies (7, 8) mounted at its mast foot (5)and mast head (6), and a displacement mechanism acting by means of afriction lock and displaceable along the bottom guide track serves as abottom displacement drive (13) and a displacement mechanism acting bymeans of a friction lock and displaceable along the top guide trackserves as a top displacement drive (14), the bottom and top displacementmechanisms being guided on the guide tracks by means of height andlateral guide elements (20, 24) and displaceable relative to the guidetracks by means of a drive system (33) with at least one drive roller(37), and the displacement mechanisms are drivingly connected to themast (2), wherein a coupling mechanism (29) is provided respectivelybetween the guided, displaceable displacement drives (13, 14) and bogieassemblies (7, 8), comprising at least two coupling parts (28, 40)displaceable towards one another perpendicular to the longitudinalextension of the guide track, and at least one coupling connection (27)extending between the articulation axes (42 a, 42 b) of the couplingparts (28, 40), which are mounted so as to pivot about the articulationaxes (42 a; 42 b) substantially perpendicular to the longitudinalextension of the guide track relative to a coupling part (28; 40), andto slide at an end region remote from these articulation axes (42 a; 42b) by means of a longitudinal guide (44) in a direction substantiallyparallel with the longitudinal extension of the mast (2).
 103. Rackserving device as claimed in claim 102, wherein the first coupling part(28) is disposed on the mast (2) in the region of the mast foot (5) andmast head (6) and the other coupling part (40) is disposed on thedisplacement drive (13, 14), and the coupling connection (27) extendsbetween the coupling parts (28, 40) and is articulatingly linked tothem.
 104. Rack serving device as claimed in claim 103, wherein thefirst mast-side coupling part (28) is offset transversely to thehorizontal guide track part (19) of the guide track in the directiontowards the mast foot (5) or in the direction away from the mast foot(5).
 105. Rack serving device as claimed in claim 103, wherein the firstmast-side coupling part (28) is offset transversely to the guide trackpart (19) of the guide track in the direction of the mast head (6) or inthe direction away from the mast head (6).
 106. Rack serving device asclaimed in claim 102, wherein the bottom and top guide track areprovided in the form of a bottom and top runner rail (11, 12) with apreferably I-shaped cross section, and at least one height guide element(20) and lateral guide elements (24) of a guide mechanism of the bottombogie assembly (7) lie against a horizontal guide track part (19) of atop belt (18) and against a vertical guide track part (10) of a web (17)of the bottom runner rail (11), and lateral guide elements (24) of aguide mechanism of the top bogie assembly (8) sit against a verticalguide track part (10) of a web (17) of the top runner rail (12). 107.Rack serving device as claimed in claim 102, wherein each of thedisplacement drives (13, 14) co-operates with at least two pairs ofheight guide elements (30) spaced at a distance apart from one anotherin the aisle direction (15) on either side of the web (17) of thepreferably I-shaped runner rails (11, 12) lying against mutually remoteguide track parts (19, 32) of the bottom and top runner rail (11, 12),and has at least one contact element (36) lying against mutually remoteguide track parts (32, 19) of the bottom and top runner rail (11, 12)and at least two pairs of lateral guide elements (31) spaced at adistance apart from one another in the aisle direction (15) lyingagainst oppositely lying guide track parts (10) of the web (17). 108.Rack serving device as claimed in claim 104, wherein the height guideelements (30) are disposed so that they can roll on guide track parts(19, 32) and contact elements (36) which can be pressed against theguide track parts (32, 19) are provided in the form of height guiderollers and pressure rollers rotating about axes (34) extendingtransversely to the longitudinal extension of the runner rails (11, 12),and the adjacent rolling lateral guide elements (31) are provided in theform of lateral guide rollers rotating about rotation axes (35)extending perpendicular to the aisle direction (15) and the longitudinalextension of the runner rails (11, 12).
 109. Rack serving device asclaimed in claim 102, wherein the height and lateral guide elements (30,31) of the displacement drives (13, 14) are provided in the form ofguide bars which can be pressed against the guide track parts (19, 32,10) of the runner rails (11, 12) with a pre-definable contact force.110. Rack serving device as claimed in claim 107, wherein thedisplacement drives (13, 14) have at least one driven drive roller (37)and at least one follower wheel or another driven drive roller (37),which are respectively applied against the oppositely lying guide trackparts (10) of the webs (17) of the runner rails (11, 12), and the driveroller (37) and the follower wheel or the other drive roller (37) isdisposed between the height guide elements (30) arranged one after theother.
 111. Rack serving device as claimed in claim 102, wherein theheight and/or lateral guide elements (30, 31) of the displacement drives(13, 14) are respectively disposed on a common support frame and theheight and/or lateral guide elements (30, 31) can be pressed against theguide track parts (19, 32, 10) of the runner rails (11, 12) due to theeffect of at least one pressing force acting on the support frame. 112.Rack serving device as claimed in claim 102, wherein the high andlateral guide and contact elements (20, 24; 30, 31, 36) of the bogieassemblies (7, 8) and displacement drives (13, 14) are made fromelastomers, preferably thermoplastic materials, or from steel enclosedin a plastic sheath.
 113. Rack serving device as claimed in claim 102,wherein the mast (2) is essentially vertically aligned and the bottomand top displacement drives (13, 14) are preferably arranged one abovethe other on a rear face of the mast (2).
 114. Rack serving device asclaimed in claim 102, wherein the displacement drives (13, 14) and themast (2) with the bogie assemblies (7, 8) respectively form a singleunit and the bogie assemblies (7, 8), to which a forward motion can betransmitted via the coupling part (28), are connected to thedisplacement drives (13, 14), preferably releasably.
 115. Rack servingdevice as claimed in claim 102, wherein the non-driven bogie assemblies(7, 8) are constituted by the mast (2) or are rigidly connected to themast foot (5) and mast head (6).
 116. Rack serving device as claimed inclaim 102, wherein the bogie assemblies (7, 8) each have a runner (46)which can be displaced in a pivoting motion about a mid-axis extendingtransversely to the aisle direction (15), and the runner (46) at leastpartially engaging round the runner rails (11, 12) has a U-shaped crosssection and has lateral guide elements (24), preferably on its legs (47)extending parallel with the web (17), which lie against the guide trackparts (10) of the webs (17).
 117. Rack serving device as claimed inclaim 116, wherein the runner (46) of the bogie assemblies (7, 8)supporting the lateral guide elements (24) can automatically be returnedto a predefined horizontal position by means of mechanically and/orelectrically and/or hydraulically and/or pneumatically operated means,in particular return elements (50), if the mast (2) assumes a crookedposition.
 118. Rack serving device as claimed in claim 116, wherein abase (48) extending between the legs (47) is fitted with at least onewiper bar (49) on its bottom face directed towards the guide track part(19) which is adapted to the guide track part (19) and sits against it,which is capable of generating a contact force in the direction of therunner rail (11, 12).
 119. Rack serving device as claimed in claim 118,wherein elastic return elements (50) are spaced at a distance apart fromone another between the base (48) and wiper bar (49) and on either sideof the transverse mid-axis thereof, and the wiper bar (49) is pivotableabout its transverse mid-axis, the wiper bar (49) being made fromwear-resistant plastic such as polytetrafluoroethylene, polyamide. 120.Rack serving device as claimed in claim 102, wherein the displacementdrives (13, 14) are linked, preferably releasably, via the couplingmechanism (29) to the mast foot (5) and mast head (6) and/or the bogieassemblies (7, 8) without any clearance in the aisle direction (15).121. Rack serving device as claimed in claim 102, wherein the couplingmechanisms (29), guided and displaceable on the runner rails (11, 12)between the bogie assemblies (7, 8) and displacement drives (13, 14)arranged one after the other in the aisle direction (15), and/or thedisplacement drives (13, 14, themselves are designed to compensate fordeviations in the linearity of the rectilinear guide tracks.
 122. Rackserving device as claimed in claim 102, wherein the height and lateralguide elements (30, 31) and drive rollers (37) and contact elements (36)of the displacement drives (13, 14) are disposed on a guide carriagewhich can be displaced along a guide mechanism transversely to the aisledirection (15) and runner rails (11, 12), and the guide carriage isdesigned to be displaceable relative to a housing (38) of thedisplacement drive (13, 14).
 123. Rack serving device as claimed inclaim 102, wherein the rod-like or fork-like coupling connection (27)has at least two articulation axes (42 a, 42 b).
 124. Rack servingdevice as claimed in claim 123, wherein the coupling mechanism (29) islinked via a first mast-side articulation axis (42 a) to at least onecoupling part (28) rigidly coupled with the mast (2), in particular withthe bogie assembly (7, 8), so that it can be displaced in a pivotingmotion, and is linked to at least one coupling part (40) rigidly coupledwith the displacement drive (13, 14) via another drive-side articulationaxis (42 b).
 125. Rack serving device as claimed in claim 102, whereinthe coupling mechanism (29) has at least one, preferably two, couplingconnections (27) spaced at a distance apart from one another, themounted so as to pivot about the drive-side coupling parts (40), inparticular jaw parts (41), which are preferably triangular in shape.126. Rack serving device as claimed in claim 125, wherein, at its endregions facing the bogie assembly (7, 8), the jaw part (41) has mountedon it a rotatable guide element (43) and, relatively displaceable to it,at least one other guide element (43), essentially in the region of acentre of gravity of the jaw part (41).
 127. Rack serving device asclaimed in claim 102, wherein the coupling part (28) has twosection-type longitudinal guides (44) spaced at a distance apart fromone another with guide tracks (45) formed thereby, which complement theguide elements (43) on the jaw parts (41) in order to guide the mast (2)in its longitudinal direction.
 128. Rack serving device as claimed inclaim 102, wherein the coupling connection (27) is of a fork-type orrod-type elbow rod or a mechanically and/or electrically controllableactuator drive, in particular a length-adjustable threaded spindledrive.
 129. Rack serving device as claimed in claim 102, wherein ananti-lift device (65) is disposed respectively between the mast foot (5)and the bottom runner rail (11) and between the mast head (6) and thetop runner rail (12).
 130. Rack serving device as claimed in claim 129,wherein the bogie assembly (7, 8) is fitted with a bracket-shapedanti-lift device (65) which engages around certain regions of the runnerrail (11, 12) and is provided with support elements (67) at its freebracket end regions (66), such as skids, wheels, and if the mast (2)assumes a crooked position exceeding a pre-set threshold value, thesupport elements (67) are supported on the mutually remote guide trackparts (32) of the bottom and top runner rails (11, 12).
 131. Rackserving device as claimed in claim 102, wherein at least one positiondetection system (74) is assigned to the rack serving device (1), inparticular the mast (2) and/or the bogie assemblies (7, 8) and/or thedisplacement drives (13, 14) and/or the load-bearing means (4). 132.Rack serving device as claimed in claim 131, wherein the positiondetection system (74) is provided in the form of a navigation device, inparticular GPS, consisting of a transmitter and/or receiver unit (75) onthe rack serving device (1) and a transmitter and/or receiver unit inthe pre-definable working region.
 133. Rack serving device as claimed inclaim 131, wherein the position detection system (74) can detect thelocation of the rack serving devices (1) in the working region and/orthe position of the lift carriage (3) and/or load-bearing means (4).134. Rack serving device as claimed in claim 102, wherein at least oneimage-processing element, in particular a CCD camera or a sensor systemis assigned to the rack serving device (1), preferably in the region ofthe lift carriage (3) and/or the bogie assemblies (7, 8) and/or thedisplacement drives (13, 14).
 135. Rack serving device as claimed inclaim 102, wherein the lift carriage is guided on a guide track (54) onthe mast (2), essentially without any clearance, by means of height andlateral guide elements (53) and the load-bearing means (4) is orientedperpendicular to the mast (2), and at least one sensor system (76) isprovided in order to detect a deviation of the load-bearing means (4)from its horizontal orientation on the lift carriage or load-bearingmeans (4), and a control system is provided which detects the actualvalue and controls the horizontal orientation of the load-bearing means(4) by activating at least one displacement drive (13; 14).
 136. Rackserving device as claimed in claim 102, wherein a load (9) to be carriedby the lift carriage (3) is detected by weight measuring elements, inparticular a weighing cell, and a variable contact force of the driverollers (37) and/or contact elements (36) of the displacement drives(13, 14) is adjusted and regulated via a control system by means ofmechanically and/or electromechanically activatable actuators, such as athreaded spindle, and/or the inclination of the mast (2) can be set byvarying the position of the displacement drives (13, 14) disposed oneabove the other depending on the torque acting on them.
 137. Rackserving device as claimed in claim 102, wherein a ladder (68) can bedisplaced alongside it along at least one runner rail (11; 12) andguided in the height direction and to the side, for example for carryingout maintenance and/or repair work.
 138. Rack serving device as claimedin claim 137, wherein the ladder (68) is length-adjustable.
 139. Rackserving device as claimed in claim 137, wherein, in the standbyposition, the ladder (68) is disposed externally to a working area ofthe rack serving device (1) and is monitored in its end position bymeans of sensors disposed in the standby region.
 140. Rack servingdevice as claimed in claim 135, wherein the ladder (68) can be docked ina position alongside the rack serving device (1) and releasably securedby means of mechanical and/or electrical and/or pneumatic and/orhydraulic locking elements disposed on it and on the rack serving device(1), or it is fixed in position relative to the runner rail (11; 12),for example, by locking means.
 141. Rack serving device as claimed inclaim 137, wherein the ladder (68) has height and lateral guide rollersat its ladder foot and ladder head and at least one drive elementpreferably provided on the ladder foot and/or on the ladder head, and isguided on the guide rails (11, 12) and designed so that it canoptionally be automatically displaced, in particular by means of theremotely operable drive element.
 142. Rack serving unit, whereby severalrack serving devices (1) disposed one after the other having heightand/or lateral guide elements (20, 24) can be guided and displaced alongguide tracks by means of at least one displacement drive (13, 14), therack serving units (1) being linked to one another, wherein rack servingdevices (1) are as claimed in claim
 102. 143. Rack serving unit asclaimed in claim 142, wherein the rack serving devices (1) spaced at adistance apart from one another in the aisle direction (15) areconnected to one another, preferably releasably, by means of supportframes (73) provided between the masts (2), in particular the mast feet(5) and mast heads (6) and the load-bearing means (4), which can besynchronously displaced, are directed towards one another and at leastone of the rack serving devices (1) has at least one, preferably the topand/or bottom displacement drive (13, 14).
 144. Rack serving unit asclaimed in claim 142, wherein the rack serving devices (1) are heldtogether at a pre-definable distance and/or can be displaced at apre-definable distance from one another and a control system is providedfor controlling this distance by controlling the displacement drives(13, 14) of the rack serving devices (1), and the displaceableload-bearing means (4) are directed away from one another.
 145. Rackserving unit, in particular as claimed in claim 102, wherein the mast(2) is made up of two half-shell elongate sections (80) with asubstantially C-shaped cross section and a width (81) of a base (82) ofthe C-shaped cross section is longer than a height (83) of legs (85)substantially perpendicular thereto, and these elongate sections (80)are joined to one another in a joint plane containing an axiallyparallel plane and a plane of longitudinal symmetry (88) of the mast(2), and/or the elongate sections (80) are positively assembled by awelded joint.
 146. Rack serving unit as claimed in claim 145, whereinoutwardly directed, substantially U-shaped protuberances (86) extendingin the longitudinal direction of the mast (2) are formed with sectionstrips (87) standing proud of the base (82) when the two elongatesections (80) are joined to one another to form a hollow section, andthe section strips (87) form running surfaces (89) for running wheels(90) of the lift carriage (3) which can be guided and displaced on themast (2), the two oppositely lying running surfaces (89) of everyprotuberance (86) extending parallel with one another and in planesperpendicular to the plane of longitudinal symmetry (88), and therunning surfaces (89) of the oppositely lying protuberances (86) arealigned flush with one another.
 147. Rack serving unit as claimed inclaim 145, wherein each of the elongate sections (80) with asubstantially cross-sectional shape has a substantially L-shapedprojection (91) at its first free end, which have a first surface remotefrom the plane of longitudinal symmetry (88) as running surfaces (92)for the running wheels (90) of the lift carriage (3) displaced andguided on the mast (2) and another surface containing the plane oflongitudinal symmetry (88) as support and/or joint surfaces (93), thetwo running surfaces (92) of the projections (91) extending parallelwith one another and in a plane parallel with the plane of longitudinalsymmetry (88).
 148. Rack serving unit as claimed in claim 147, whereinthe substantially L-shaped projections (91) have longitudinal edges (94)standing proud of their free ends forming the support and/or jointsurfaces (93) substantially parallel with the plane of longitudinalsymmetry (88), which form a hollow fillet for the weld seam (97) in thejoint region (95) between the two butting adjacent elongate sections(80).
 149. Rack serving unit as claimed in claim 145, wherein, at theirother free ends lying opposite the projections (91), the legs (85) ofthe elongate sections (80) have longitudinal edges (94) forming supportand/or joint surfaces (93) standing proud substantially parallel withthe plane of longitudinal symmetry (88), which form a hollow fillet forthe weld seam (97) in the other joint region (96) between the twobutting adjacent elongate sections (80).
 150. Rack serving unit asclaimed in claim 145, wherein the joint along the hollow fillet betweenthe elongate sections (80) is a weld seam (97) extending along the mastlength.
 151. Rack serving unit as claimed in claim 145, wherein thejoint along the hollow fillet between the elongate sections (80) isprovided in the form of several mutually spaced weld seams (97) appliedintermittently along a part of the mast length.
 152. Rack serving unitas claimed in claim 145, wherein the elongate section (80) has severalslot-type cutouts (105) arranged one after the other in a row in itsbase (82).
 153. Rack serving unit as claimed in claim 145, wherein anopen side of the substantially U-shaped protuberances (86) directedtowards the plane of longitudinal symmetry (88) is closed by at leastone strip-shaped stiffening element (106) overlapping with the sideregions adjoining the protuberances (86) and the stiffening elements(106) are joined to the elongate sections (80) by means of a weldedjoint.
 154. Rack serving unit as claimed in claim 145, wherein theL-shaped projections (91) are joined to one another to form asubstantially U-shaped guide track 54 b and an open side of the guidetrack (54 b) directed towards the protuberances (86) is closed by atleast one stiffening element (106) overlapping with the side regionsadjoining the projections (91), and at least one stiffening element(106) is positively joined to the two legs (85) of the elongate sections(80) by a connecting element, e.g. a screw connection, welded joint.155. Rack serving unit as claimed in claim 153, wherein thecross-sectional shape of the stiffening element (106) more or lesscorresponds to the cross-sectional shape of the protuberance (86). 156.Rack serving unit as claimed in claim 153, wherein the stiffeningelements (106) extend along the entire mast length.
 157. Rack servingunit as claimed in claim 153, wherein several stiffening elements (106)are disposed in the direction of the mast length, one after the otherand separated from one another.
 158. Rack serving unit as claimed inclaim 153, wherein the stiffening element (106) has a first side edge(107) extending parallel with the legs (85) of the elongate section (80)and lying flat against them and another side edge (108) extendingparallel with the base (82) of the elongate section (80) and lying flatagainst it, and, optionally, at least two positioning projections (109)at one of the side edges (107; 108) arranged at a distance apart fromone another in the longitudinal direction of the stiffening element(106), parallel with the one section strip (87) and sitting flat againstthe latter.
 159. Rack serving unit as claimed in claim 153, whereinconnecting regions (106) are formed between the side edges (107, 108) ofthe at least one stiffening element (106) and the leg (85) as well asthe base (82) and the stiffening element (106) is positively connectedto the elongate section (80) in the connecting regions by means of aweld joint.
 160. Rack serving unit as claimed in claim 153, wherein thejoint between the at least one stiffening element (106) and the elongatesection (80) is provided in the form of weld seams (97) extendingcontinuously along the mast length at the side edges (107, 108) of thestiffening element (106).
 161. Rack serving unit as claimed in claim153, wherein the joint between the at least one stiffening element (106)and the elongate section (80) is provided in the form of severalmutually spaced weld seams (97) extending intermittently along a part ofthe stiffening element (106) at the side edges (107, 108).
 162. Rackserving unit as claimed in claim 145, wherein the elongate sections (80)are of a symmetrical design and have a substantially constant wallthickness (102) throughout their cross section.